Thanks to all who responded to my earlier post. A little digging has permitted me to show the problem more clearly. I would be very grateful to anyone who can identify it, or has dealt with it. (Seattle type area)
I do believe this is a type of moss causing the patches. No wonder it doesn't mind sun.....the moss is located at the very base of the grass and even below the first half inch or so of soil, so the sun doesn't reach it.
Wherever there is one of the odd looking patches, there is the moss below....and growing up with the grass a bit in shaded areas.
Its effect seems to be to stunt the grass leaves, causing them to be very narrow, short, and splitting into filimented ends, so it causes an odd looking patch.
I am not sure my moss sprayer worked properly last time, so I mixed some moss killer directly with water and put it on. I will see what happens and post it.